This trick is incredibly simple: Run back into the cryo-tube before it closes. That's it. The lid will push you into some very strange places... with this trick it is possible, with some careful jumping, to get in some places that you aren't supposed to be. If you crouch inside the tube before the lid closes, you can see the headless model of the master chief used in the intro cutscene. The following are pictures resulting from this exploit... -FrogBlast